The organization of file system metadata has important consequences for the efficiency and flexibility of storage management operations such as snapshotting and cloning. Snapshotting creates point-in-time read-only copies of a file, while cloning creates writable copies of a file. Early implementations of snapshots and clones essentially copied all file data as well as metadata. More recently, especially using techniques such as deduplication, it is more common to simply copy or manipulate metadata without having to copy the data. Some common approaches used recently include: copying all file metadata for each snapshot or clone and breaking up metadata into pages that are initially shared and performing copy-on-write, or creating new versions of metadata when they are modified.